Fukushima fallout: Fire hazard could be state’s tsunami

Editor's note: This is one of four essays on nuclear power on the first anniversary of the disaster at the Daiichi nuclear plant in Japan.

A year after the Fukushima Daiichi nuclear plant disaster in Japan, the U.S. nuclear industry and the Nuclear Regulatory Commission, its regulator, are contemplating measures to protect American reactors from similar hazards. The Fukushima disaster was caused by the one-two punch of an earthquake and tsunami, which disabled both the normal and backup power sources for the equipment needed to keep the radioactive fuel from melting. The operators were left with equipment that they were literally powerless to use, resulting in multiple reactor meltdowns.

Fukushima’s owner had known for years that the facility’s protective sea wall was not tall enough for the height of the tsunami wave that could arrive at the plant. Taller sea walls are now being erected around Fukushima and other nuclear plants.

The NRC has known for years that none of the nuclear reactors in California meet fire protection regulations. The NRC also knows that fire hazards represent roughly half of the risk of reactor core meltdown – nearly equal to all other threats combined.

Fire is a hazard for the same reasons a tsunami is. Each reactor at Fukushima was equipped with two emergency diesel generators, and only one was needed to adequately cool the core. But the tsunami disabled all of them. A fire can cause similar widespread destruction. In March 1975, a fire at the Browns Ferry nuclear plant in Alabama disabled all the emergency core cooling systems for the Unit 1 reactor. The fire damaged the electrical cables needed to power and control the emergency equipment. Only heroic worker actions prevented a reactor meltdown.

The NRC upgraded its fire protection regulations seeking to prevent another Browns Ferry fire, or worse. These regulations required the electrical cables for primary systems and their backups to be separated. The goal was to prevent a fire from disabling all the emergency systems.

Years later, the NRC’s inspectors found that many owners had not complied with its regulations. Rather than providing the mandated cable separation, many owners would allow a fire to disable cables for all emergency systems and to send workers to manually turn on emergency pumps and operate other emergency equipment.

The NRC adopted an alternate set of fire protection regulations in 2004, which seek to prevent a fire from disabling all emergency equipment via a different method. Owners could analyze the timelines associated with fires to determine whether the fires could be extinguished before they damaged too much emergency equipment.

The owners of the Diablo Canyon reactors and the San Onofre reactors informed the NRC of their intent to meet the 2004 fire protection regulations. In doing so, they have conceded that their plants also do not meet the older regulations. No owner would spend the millions of dollars necessary to achieve compliance with the newer regulations if they already met the old ones.

The NRC and the owners of the Diablo Canyon and San Onofre plants know that these plants violate fire protection regulations. They also know that fire poses a major risk of a reactor meltdown at these plants. If a big fire causes big problems at Diablo Canyon or San Onofre, the owners and the NRC will have some very hard questions to answer. When an owner or regulator are fully aware of a safety hazard and of its solution, it is guilty of nuclear negligence when the unresolved hazard causes harm.

Fukushima should teach us that the time to prepare for an emergency is before an accident happens, not afterward. It is past time for the San Onofre and Diablo Canyon plants to be prepared for a major fire.